Over 500 Italian cities, towns and villages have signed up to a campaign aimed at raising public awareness about energy consumption.
This Friday's annual event seeks to draw attention to energy usage by calling on people nationwide to switch off their lights at the same time.
Now in its fourth year, 'M'illumino di Meno' (less lights) has wider support than ever, with a record number of local authorities joining in.
All public buildings and offices in participating areas will turn off their lights at 6pm for 90 minutes on Friday, as will hundreds of museums, universities, retail outlets, sports clubs and private companies.
The Italian public has also been invited to switch off all lights and appliances that are not absolutely necessary, while lighting will be cut at a series of key Italian sites.
The Colosseum, the Pantheon, the Trevi Fountain, the Italian parliament, Saint Mark's Square in Venice, the Milan Duomo and the Verona Arena will be among the many monuments plunged into darkness.
''Using and saving energy is one of the most important issues for local authorities in the new millennium,'' commented Giacomo D'Arrigo, coordinator of the youth section of the Italian Association of Italian Municipal Councils (ANCI).
''Raising awareness among the public and young officials, who number some 30,000, with symbolic initiatives such as this is a really good way to draw attention to the issue''.
Addressing a press conference ahead of the event, the chair of the World Energy Council board, Chicco Testa, highlighted the importance of local administrations in fighting global warming.
''Town councils will play a crucial role in this campaign, which is vital both for reducing our dependence on fossil fuels, as well as cutting greenhouse gases,'' said Testa.
The Italian initiative was launched by one of Italy's largest live radio stations, Caterpillar, in 2005.
The event is partly timed to coincide with the show, which broadcasts at 6pm, but also to maximize coverage and attention, as people arrive home from work.
Millions of Italians participated in the event last year, said organizers.
The 'M'illumino di Meno' campaign will peak in the evening but the entire day will be focused on raising awareness about climate change and energy consumption.
Global warming is caused mainly by the burning of fossil fuels, which leads to the emission of greenhouse gases such as carbon dioxide.
While renewable energy sources are part of the solution, experts say people must learn to use less energy, because these sources alone are unable to support current demand.
Italy is one of several countries to launch energy-saving days in recent years.
France celebrates its energy awareness day on February 1, while the lights will be switched off in Britain at the end of the month, on February 27.
Italy chose February 16 because it marks the anniversary of the day the Kyoto protocol - which sets signatory nations' greenhouse gas targets - came into effect in 2005.
